This invention relates to packing elements for use in chemical process equipment. It relates specifically to random packing elements of a novel and advantageous design useful in mass transfer applications.
"Mass transfer" has been defined as the transfer of one or more components from one immiscible phase to another. This "component" may be a chemical or it may be heat. In the case in which the component is heat this may be combustion heat or reaction heat that needs to be removed from a reaction stream before further processing, or from a hot stream of fluid before it can be collected or used. The component can also be a chemical such as a gas component to be removed from a gas stream by absorption, or a component of a liquid mixture to be treated by a distillation or separation process. For such applications and a plurality of other applications involving mass transfer, it is conventional to pass the fluid to be treated through a column containing randomly disposed packing elements. These elements are hereinafter referred to as mass transfer elements for simplicity, regardless of the actual process in connection with which they are actually designed to be used.
Clearly the most efficient mass transfer elements are those that present the largest surface area to the fluid for contact. There have therefore been many attempts to design random packing elements with this surface area feature maximized. It is found however in practice that other characteristics are also extremely desirable. For example, it is also valuable if the elements do not nest together when in the column because this reduces the effective surface area exposure. It is also important that the elements do not pack so tightly as to restrict the fluid flow and generate a large pressure drop between the entrance and exit of the column.
The balancing of these often competing requirements to produce an effective mass transfer element is a matter of considerable skill and involves compromises to achieve the optimum combination of properties.